Double ring tone heard over SIP trunk

[Stuart Cross]

Hello, 

I have a SIP trunk configured from CUCM to talk to a 3rd party service providing and IVR.  When calls are placed across the SIP trunk I hear a double ring tone.  I only get this when calling internally across the trunk, external calls I don't get the same issue.  

Calls still work fine, but is there a way to stop this internally?  I have tried to change the call classification on the trunk to on net, as there were some posts saying this would fix the issue, however it hasn't made a difference.

thanks

[Muaaz El Kamali]

Hi Stuart,

Can you check under route pattern if you have outside dial tone or not? but unlikely to cause this issue.

Also this is issue can happen from the other side if the call forward to other number you can check that part. 

Regards, 

Muaaz

[Stuart Cross]

Hi, 

No route pattern does not have the "provide outside dial tone" checked.  The other side of the trunk is an IVR server.  So the call flow is.

IP Phone ==> CUCM SIP trunk ===>3rd party server ===>Script DN.  The DN in this case is 8272 which is tied to the script.

Thanks

[Julie Oblak]

We just upgraded to cucm 12.5 and now have the same issue.  IP Phone ==> CUCM SIP trunk ===>3rd party server ===>Script DN and when the call is delivered the person at the phone hears the double ringer.